The installation of mechanical components upon a shaft often requires special tools for producing the necessary axial force to assemble the parts. For instance, wheels, gears, collars, sleeves, and the like are commonly installed upon shafts, within or without keys, by the use of presses or arbors for producing the necessary axial force on the component being mounted on the shaft.
Where installation of a part upon a shaft cannot be accomplished by a conventional arbor or press, it is known to provide the shaft with a shoulder, recess, or the like which may be engaged by installation equipment to force the part upon the shaft. Also, it is known to provide the end of the shaft with a threaded hole, or a threaded stud, wherein the desired axial forces may be achieved.
For instance, U.S. Pat. Nos. 1,521,202 and 3,490,132 disclose tools used in conjunction with shaft mounted parts wherein a threaded hole in the end of the shaft is used to support the tool during use. With this type of device, it is necessary, of course, that the threaded portion of the tool received within the threaded shaft bore have threads complimentary to each other in order to achieve the desired connection. Accordingly, a tool must be specifically designed for use with a particular shaft and threaded hole, and such a tool does not have "universal" application.
Harmonic balancers are commonly installed upon the nose end of the crankshaft of an internal combustion engine for the purpose of absorbing and dissipating crankshaft vibrations. Such balancers normally incorporate elastomer vibration dampening elements, and often function as a drive pulley engagable by a belt for supplying power to alternators, power steering pumps, air conditioners, and the like. As the harmonic balancer is mounted at the lower region of the engine access thereto is usually limited, and considerable difficulty is often experienced in the servicing of harmonic balancer wherein a new balancer must be installed upon the crankshaft end.
Complicating the installation of harmonic balancers upon a crankshaft is the fact that while the end of an internal combustion engine crankshaft is commonly provided with a threaded hole, the size and thread specifications of such holes will vary between engine manufacturers, the size or model of engine, and other specification variations. Accordingly, it is necessary to utilize a balancer installation tool having the specific thread specifications which match with the crankshaft threaded hole, and with prior balancer installation tools, the need for a number of various size tools places an economic burden upon the mechanic, and complicates engine servicing.
It is an object of the invention to provide an installation tool for a harmonic balancer for internal combustion engine crankshafts wherein a single tool has "universal" aspects wherein the tool may be used with a wide variety of engine crankshafts having threaded holes of various specifications.
Another object of the invention is to provide a tool for installing balancers upon engine crankshafts utilizing a crankshaft threaded hole wherein a small threaded adapter is used to accommodate the tool to a specific crankshaft, and the adapter is received within a recess within the tool.
Yet another object of the invention is to provide a universal balancer installation tool wherein a plurality of threaded adapters may be used therewith, and only the adapter is required to be changed to accommodate the tool to various sizes of crankshafts having threaded end holes.
An additional object of the invention is to provide an installation tool for crankshaft harmonic balancers wherein selective threaded adapters may be quickly and readily installed within a common tool, and wherein an economical tool is provided for accommodating a wide variety of crankshafts.
In the practice of the invention the tool includes an elongated shaft exteriorly threaded throughout its length. The shaft includes an inner end which, during use, is located adjacent and coaxial to the nose end of an engine crankshaft. The shaft includes an outer end which is preferably provided with torque transfer means in the form of a pair of parallel wrench engaging flats.
The shaft is provided with a longitudinal bore throughout its length, and at its inner end a recess of a diameter larger than the bore is located. The recess is of a cylindrical configuration and selectively receives a threaded adapter of a length greater than the recess which has an exteriorly threaded portion capable of being threaded into the threaded hole located at the end of the crankshaft to be serviced. The adapted also includes an inner portion located within the shaft recess, and this inner portion has a recessed surface upon which indicia is located indicating the specifications of the particular adapter.
A bolt is rotatably received within the shaft bore, and the inner end thereof threads into a threaded bore defined in the adapter. The head of the bolt is located adjacent the outer end of the shaft, and tightening of the bolt firmly draws the adapter into the shaft recess affixing the adapter to the shaft in an integral assembly therewith.
The threaded shaft is mounted upon the end of the crankshaft by means of the adapter threading into the hole in the crankshaft end wherein the shaft is coaxially aligned with the crankshaft nose. A harmonic balancer is placed upon the shaft and initially aligned with the crankshaft end. Thereupon, an annular thrust bearing is slipped over the shaft, and a forcing nut is threaded upon the shaft threads against the thrust bearing. The thrust bearing is of a diameter greater than the bore of the balancer, and as the nut is rotated upon the shaft the thrust bearing is forced against the balancer forcing the balancer upon the crankshaft end.
Upon the balancer being fully installed upon the crankshaft the shaft may be rotated to unthread the adapter from the crankshaft threaded hole, and the tool is removed, the assembly of balancer and crankshaft being accomplished.
Accordingly, it will be appreciated that by selecting the proper adapter a single tool may be used with a wide variety of crankshafts, and as the adapters are of a relatively small size requiring little material a plurality of adapters may be packaged with a single shaft, bolt, thrust bearing and nut to provide a universal tool which may be readily used with a wide variety of crankshafts.